Radio signaling system



Jan. 10, 1928. 7 1,655,961 L. KUHN RADIO SIGNALING SYSTEM Filed Aug. 26. 19 1 /7. F Gene/afar.-

A TT RNE Y lit Patented Jan. 10, 1928.

UNITED STATES PATENT OFFICE.

L'UIl'WIf-l Kil'HN, 0F BERLIN, GERMANY, ASSIGNOR '10 WESTINGHOUSE EIIEGTRIG & MANUFACTURING COMPANY, A. GORIPORATIUN U13 LE'IENlllSYLVANIA.

RADIO FBIGNALING SYSTEM.

application file! August 26*, 1921, Serial No. 495,738, and in Germany August 18, 19:20.

tGRKNTEIl UNDER THE PRUVISIONS THE A01 01? MARCH 3, 1921, 41 E'LA'l. 13., 1313.)

This invention relates to radio com1nunication systems, more particularly transmission systems employing vacuum tube esc1llators which generate continuous waves modulated at an audible frecpiency. It has been shown previously that signals, particularly speech, can be transmitted by a vacuum tube oscillator in which the ener y output is constant. F a

lo accomphsh this, a modulator tube is employed the grid potential of which is varied in accordance with the speech frequency.

Instead of influencing the grid of the modulator tube by means of speech fretpuency, it is proposed by the present invention to influence the grid at an autlible frequency which may be constant and not necessarily varied in accordance with speech. It is proposed to use a high frequency generator the output of which is used to vary the grid potential of the modulator tube. A lrey may be inserted in the output circuit of the audiodrequency generator to permit the sending of characters in any sequence desired. It is possible when using an audiofrequency current generator for the grid of the modulator tube, to rectify a portion of the output and use the rectified cur-- rent as a source of energy for the plate circults of both the oscillator and modulator tubes.

A clearer understanding of the invention may be had by reference to the following description of a preferred embodiment which is illustrated in the accompanying drawings. in these drawings there is shown a schematic arrangement of a vacuum tube oscillator the output of which is modulated by a modulator tube, the resistance of which is varied by impressing an audio-frequency potential on the grid.

Referring now to the drawing, a vacuum tube oscillator of the usual form is represented at 1 and its modulator tube is represented at Q. The modulator tube is connected to the oscillator tube in the well-known manner whereby the energy output of the oscillator tube is maintained constant. The grid cir cuit of the modulator tube 2 is coupled. by means of an audio-frequency transformer 6 to an audiofrequency alternator 3. A key 5 may be inserted in this circuit to permit the interruption of the wave train to form signals of any desired sequence. In order to obtain the necessary energy for the output circuits of the vacuum tubes, a portion of the output of the alternator 3 is rectified by means of the vacuum tube rectifier 4, which has in series with its output circuit a choke coil 7.

The fundamental idea of the invention can of course be used in a variety of ways. For example, the modulator tube may be influenced by a separate alternating current ma chine and the output circuits of the vacuum tubes may be supplied with energy from a source of direct current.

I claim":

1. In a radio transmitting system, a vacuum tube oscillator having an anode, a vacuum tube modulator having an anode and a grid, a conductive connection between said anodes a rectifier having an output circuit connected to said anodes and an input-circuit energized from a source of audio-frequency alternating current, and means for coupling said source to the grid of said modulator tube, whereby the oscillator tube is positively modulated at the frequency of said source.

2. A wave signaling system comprising a vacuum tube oscillator having input and output circuits, a modulator tube having input and output circuits, the output circuits of both tubes being conductively connected and supplied from a rectifying device, an audiofrequency alternating current generator arranged to energize said rectifier, means for coupling the generator to the input circuit of the modulator tube, and a keying device in circuit with said coupling means.

In testimony whereof I affix my signature.

Du. Inc. LUDWIG Kill-IN. 

